The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Presently, individuals communicating over a network, such as a wide area network like the Internet, operate in what is generally referred to as an “enterprise environment.” In an enterprise environment, the communications means available to users are generally reliable and adequate in bandwidth to meet the needs of most users. Information services such as email, on-line search engines (e.g., GOOGLE®, YAHOO®, etc.) and directory lookup are generally accessible and reliable without significant connection issues, and thus are often taken for granted. In the enterprise environment, other resources that a user may wish to access and collaborate with are often available without any significant delay in connectivity and without interruption in connectivity. Thus, the individual is able to make informed decisions or to carry out actions after considering the obtained information.
A tactical environment, however, is dynamic with information providers and consumers joining and exiting the network at various times. For a tactical environment, the availability of the right data at the right time, for the right person is vital to decision making and mission success. Net Centric Operations in the tactical environment are often subject to conditions of low bandwidth, high jitter and intermittent connectivity. In addition, other information services such as messaging, data storage and information discovery may be marginal in performance or simply not available. Participants in this environment are often ad hoc participants, meaning that they join and leave the network unpredictably. Interactions between these participants, via their hardware and software, can be interrupted or degraded by the absence of the other participants that one may be relying on. When this happens, some participants may have not have the information or data needed for making sound decisions.
Additionally, the infrastructure employed in a tactical environment may be limited, which can result in intermittent connectivity between users and systems that provide needed information. Thus, a user may encounter a situation where one or more information providers are temporarily unavailable when the user is attempting to obtain needed information from the provider(s), and where the information the user is attempting to obtain needed is important to making a mission decision. In such event, the user may need to make a decision without the benefit of having been able to obtain and consider the most pertinent information.
Currently, the “Publish and Subscribe” approach provides one way to mitigate the problem of lack of timely information. This technique first requires topics to be created by information providers. Topics must be set up prior to use by providers that publish data into an appropriate topic. Consumers can then subscribe to a certain topic of interest to obtain the data.
The “Publish and Subscribe” approach has several limitations. For one, it is not practical to maintain a list of topics in a changing environment (e.g., a tactical environment where individuals or assets are entering or leaving the environment) or where it is difficult to predict what the topics will be. It also requires active management by both the data publisher and data subscriber. In other words, providers have to actively put information, or at least the metadata of information, into the topic bins. Consumers are then required to go to the appropriate bins to obtain the information of interest. Consumers must also determine which information is relevant to the transaction request at hand. This task is often too burdensome for most consumers or users, especially in a rapidly changing environment such as a tactical environment. Overall, the Publish and Subscribe method may be acceptable for well structured small groups but it quickly becomes unmanageable for larger or ad hoc networks.